Wireless communication apparatus and method

ABSTRACT

A wireless communication apparatus includes multiple antenna devices, a signal generator, a phase shifter, a phase controller, and a quadrature error corrector (phase error corrector and amplitude error corrector). The signal generating circuitry, in operation, generates an IQ signal having an I signal and a Q signal. The plurality of phase shifting circuitry provided for each of the plurality of antenna devices, in operation, generates a plurality of combination signals by combining the I signal and the Q signal based on a predetermined combining scheme. The phase controlling circuitry, in operation, controls the predetermined combining scheme in each of the plurality of phase shifting circuitry. The quadrature error correcting circuitry, in operation, corrects at least one of amplitude combining scheme and phase combining scheme of the predetermined combining scheme in a correction of the predetermined combining scheme.

BACKGROUND

1. Technical Field

The present disclosure relates to a wireless communication apparatus andmethod for transmitting IQ signals in a phased array system.

2. Description of the Related Art

A phased array system that performs directivity communication by usingmultiple antenna devices is attracting attention in various fields (forexample, see RACZKOWSKI Kuba, et al., “A Wideband Beamformer for aPhased Array 60 GHz Receiver in 40 nm Digital CMOS”, Dig Tech Pap IEEEInt Solid State Circuits Conf, 2010, p. 36-38.). It may be possibleenhance the communication efficiency by the application of IQ modulationto the phased array system.

However, quadrature errors, such as phase errors and amplitude errors,may occur between an in-phase signal (I signal) and a quadrature signal(Q signal) which form an IQ signal. In the case of the phased arraysystem, such quadrature errors may occur in each of the multiple antennadevices.

An example of the technology for correcting IQ signals for quadratureerrors is disclosed in International Publication No. 2011/121979. Inthis technology (hereinafter referred to as “the related art”), an IQcorrecting circuit corrects two local (LO) signals out of phase witheach other for quadrature errors so as to generate an I local signal anda Q local signal. Then, the generated I local signal and Q local signalare separately input into quadrature mixers disposed in two basebandsignal systems.

By applying the related art to a phased array system, wirelesscommunication using directivity-controlled IQ signals may be performedwith reduced quadrature errors.

SUMMARY

In this case, however, it is necessary to provide an analog circuit forcorrecting for quadrature errors for each antenna device, whichincreases the circuit scale.

One non-limiting and exemplary embodiment of the present disclosureprovides a wireless communication apparatus and method that is able toperform directivity communication by using IQ signals corrected forquadrature errors, substantially without increasing the circuit scale.

In one general aspect, the techniques disclosed here feature a wirelesscommunication apparatus including a plurality of antenna devices, signalgenerating circuitry, a plurality of phase shifting circuitry, phasecontrolling circuitry, and quadrature error correcting circuitry. Thesignal generating circuitry, in operation, generates an IQ signal havingan I signal and a Q signal. The plurality of phase shifting circuitryprovided for each of the plurality of antenna devices, in operation,generates a plurality of combination signals by combining the I signaland the Q signal based on a predetermined combining scheme. The phasecontrolling circuitry, in operation, controls the predeterminedcombining scheme in each of the plurality of phase shifting circuitry.The quadrature error correcting circuitry, in operation, corrects atleast one of amplitude combining scheme and phase combining scheme ofthe predetermined combining scheme in a correction of the predeterminedcombining scheme.

It should be noted that general or specific embodiments may beimplemented as a device, a system, a method, an integrated circuit, acomputer program, a storage medium, or any selective combinationthereof.

According to an aspect of the present disclosure, it is possible toperform directivity communication by using IQ signals corrected forquadrature errors, substantially without increasing the circuit scale.

Additional benefits and advantages of the disclosed embodiments willbecome apparent from the specification and drawings. The benefits and/oradvantages may be individually obtained by the various embodiments andfeatures of the specification and drawings, which need not all beprovided in order to obtain one or more of such benefits and/oradvantages.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of the configuration of a wirelesscommunication apparatus according to a first embodiment of the presentdisclosure;

FIG. 2 illustrates an example of the configuration of a phase shifter inthe first embodiment;

FIG. 3 illustrates details of an example of the configuration of thephase shifter in the first embodiment;

FIG. 4 illustrates an example of a partial circuit configuration of thephase shifter in the first embodiment;

FIG. 5 illustrates an example of the configuration of a gm amplifier inthe first embodiment;

FIG. 6 conceptually illustrates an example of the state in whichquadrature errors are corrected in the first embodiment;

FIG. 7 illustrates an example of the detailed configuration of a phasecontroller in the first embodiment;

FIG. 8 illustrates an example of the configuration of a wirelesscommunication apparatus according to a second embodiment of the presentdisclosure;

FIG. 9 conceptually illustrates an example of the state in whichquadrature errors are corrected in the second embodiment;

FIG. 10 illustrates an example of the detailed configuration of a phasecontroller in the second embodiment;

FIG. 11 illustrates an example of the configuration of a wirelesscommunication apparatus according to a third embodiment of the presentdisclosure; and

FIG. 12 illustrates an example of the configuration of a wirelesscommunication apparatus according to a fourth embodiment of the presentdisclosure.

DETAILED DESCRIPTION

Embodiments of the present disclosure will be described below in detailwith reference to the accompanying drawings.

First Embodiment

In a first embodiment of the present disclosure, an example of awireless communication apparatus that transmits a radio signal by usingan array antenna including N antenna devices will be discussed.

(Configuration of Wireless Communication Apparatus)

The configuration of the wireless communication apparatus according tothe first embodiment will first be discussed below.

FIG. 1 is a block diagram illustrating an example of the configurationof a wireless communication apparatus 100 according to the firstembodiment. In FIG. 1, the configuration of the wireless communicationapparatus 100 including an array antenna constituted by N antennadevices is shown.

As shown in FIG. 1, the wireless communication apparatus 100 includes asignal generator 110, a digital-to-analog (D/A) converter (DAC) 120,first through N transmission branches 130 ₁ through 130 _(N), and aphase controller 140.

The signal generator 110 generates a digital IQ signal indicatinginformation to be transmitted.

The D/A converter 120 performs D/A conversion to convert the generateddigital IQ signal to an analog IQ signal.

The first through N transmission branches 130 ₁ through 130 _(N) providedifferent phases to the analog IQ signal so as to convert the analog IQsignal into radio frequency (RF) signals.

Each of the transmission branches 130 includes a phase shifter 131, asignal mixer 132, an RF transmitter 133, and an antenna device 134.

On the basis of control values supplied from the phase controller 140,the phase shifters 131 of the respective transmission branches 130provide different phases to the analog IQ signal.

FIG. 2 shows an example of the configuration of the phase shifter 131through illustration of calculations performed by the phase shifter 131.FIG. 3 illustrates details of an example of the configuration of thephase shifter 131 shown in FIG. 2.

In FIGS. 2 and 3, each of first through fourth multiplication blocks 210₁ through 210 ₄ integrates therein a circuit for multiplying an inputcurrent by a control value supplied from the phase controller 140 so asto amplify (“amplify” includes attenuate) the input signal in accordancewith the magnitude of the control value. The control value may be apositive value or a negative value. Accordingly, each of the firstthrough fourth multiplication blocks 210 ₁ through 210 ₄ has both of afunction of outputting a current and a function of receiving a current.

An I component (Iin/IP_IN and IN_IN, hereinafter referred to as the “Isignal”) of the IQ signal is input into the first and thirdmultiplication blocks 210 ₁ and 210 ₃. A Q component (Qin/QP_IN andQN_IN, hereinafter referred to as the “Q signal”) of the IQ signal isinput into the second and fourth multiplication blocks 210 ₂ and 210 ₄.

The phase shifter 131 outputs the value obtained by adding output fromthe first multiplication block 210 ₁ and output from the secondmultiplication block 210 ₂ to each other, as a new I signal (Iout/IP_OUTand IN_OUT) of the IQ signal. The phase shifter 131 also outputs thevalue obtained by adding output from the third multiplication block 210₃ and output from the fourth multiplication block 210 ₄ to each other,as a new Q signal (Qout/QP_OUT and QN_OUT) of the IQ signal.

As the control values, for example, values of cos θ, −sin θ, sin θ′, andcos θ′, are respectively supplied to the first through fourthmultiplication blocks 210 ₁ through 210 ₄. The control values suppliedto the first through fourth multiplication blocks 210 ₁ through 210 ₄will be called first through fourth control values, respectively.

In this case, the phase shifter 131 performs processing for generating anew I signal by adding the value obtained by multiplying the value ofthe I signal by the first control value (cos θ) and the value obtainedby multiplying the value of the Q signal by the second control value(−sin θ) to each other. The phase shifter 131 also performs processingfor generating a new Q signal by adding the value obtained bymultiplying the value of the I signal by the third control value (sinθ′) and the value obtained by multiplying the value of the Q signal bythe fourth control value (cos θ′) to each other.

To put it another way, the above-described processing is equal to rotatecalculations for the I signal and the Q signal. More specifically, ifθ′=θ, the phase shifter 131 performs operation equal to rotate operationfor rotating the I signal and the Q signal by the angle θ by multiplyingthe coordinates (constellation) of the input IQ signal by a rotationmatrix. That is, the phase shifter 131 is able to obtain output which isequivalent to the result of performing phase rotation on the inputsignal by the angle θ upon receiving cos θ, −sin θ, and cos θ as thefirst through fourth control values.

As a result of supplying control values corresponding to differentvalues of θ to the phase shifters 131 (transmission branches 130),different phases θ are applied to the IQ signal for the transmissionbranches 130, thereby implementing desired beamforming (directivitycontrol).

FIG. 4 illustrates an example of a partial circuit configuration of thephase shifter 131. In FIG. 4, the circuit configuration corresponding toa system of the first and second multiplication blocks 210 ₁ and 210 ₂in a case in which each multiplication block 210 conducts gainadjustment of five bits (2⁵ stages) is shown.

As shown in FIG. 4, the phase shifter 131 includes five-stage amplifiers211 having different amplification factors ×1, ×2, . . . , ×16 for eachof the I signal and the Q signal. A control value for controlling theamplification factor of each amplifier 211 is a digital control signal,and the input and output values of each amplifier 211 are analogsignals.

Each amplifier 211 is formed by connecting gm amplifiers(transconductance amplifiers) (not shown). The number of gm amplifiersis a power of two corresponding to the number of bits. The gm amplifieris an amplifier that serves as a non-inverting amplifier when a controlsignal I_ENP is enabled and that serves as an inverting amplifier when acontrol signal I_ENN is enabled. That is, each amplifier 211 isconfigured to output a positive current by making the control signalI_ENP active and to output a negative current by making the controlsignal I_ENN active.

Outputs from the amplifiers 211 are added. That is, the gm gain for eachof the I signal and the Q signal linearly changes in accordance with thebinary control signals I_ENP, I_ENN, Q_ENP, and Q_ENN. In themultiplication block 210, as a whole, by controlling the control signalsI_ENP and I_ENN of each bit, 2⁵-stage gain control can be performed foreach of positive components and negative components.

The phase shifter 131 also has a similar circuit configurationcorresponding to a system of the third and fourth multiplication blocks210 ₃ and 210 ₄, though such a configuration is not shown.

FIG. 5 illustrates an example of the configuration of a gm amplifier.

As shown in FIG. 5, a gm amplifier (transconductance amplifier) 212includes first through sixth MOS (Metal-Oxide-Semiconductor) transistorsM1 through M6.

A non-inverting input voltage signal and an inverting input voltagesignal are input into the gates of first and second MOS transistors M1and M2, respectively. Drain output currents of the first and second MOStransistors M1 and M2 have a form in which the gate input voltages areinverted. That is, the first and second MOS transistors M1 and M2 form apseudo differential amplifier.

The drain of the first MOS transistor M1 is connected to the sources ofthe third and fourth MOS transistors M3 and M4, while the drain of thesecond MOS transistor M2 is connected to the sources of the fifth andsixth MOS transistors M5 and M6. A control signal ENP is input into thegates of the fourth and fifth MOS transistors M4 and M5, while a controlsignal ENN is input into the gates of the third and sixth MOStransistors M3 and M6.

When the control signal ENP is Hi (high) and the control signal ENN isLo (low), the fourth and fifth MOS transistors M4 and M5 are turned ON.The output current of the first MOS transistor M1 passes through thefourth MOS transistor M4 and is output to the inverting output, whilethe output current of the second MOS transistor M2 passes through thefifth MOS transistor M5 and is output to the non-inverting output. Inthis case, the gm amplifier 212 serves as a non-inverting amplifier.

In contrast, when the control signal ENP is Lo and the control signalENN is Hi, the third and sixth MOS transistors M3 and M6 are turned ON.The output current of the first MOS transistor M1 passes through thethird MOS transistor M3 and is output to the non-inverting output, whilethe output current of the second MOS transistor M2 passes through thesixth MOS transistor M6 and is output to the inverting output. In thiscase, the gm amplifier 212 serves as an inverting amplifier.

In this manner, the gm amplifier 212 (and the amplifier 211 constitutedby gm amplifiers) is capable of changing the signs of the output valuesin accordance with the values (control values) of the control signals.

With the above-described configuration, the phase shifter 131 combinesthe I signal and the Q signal in accordance with the control values soas to output a phase-adjusted IQ signal. That is, by combining the Isignal and the Q signal, the phase shifter 131 generates a signalequivalent to a signal obtained by rotating the phase of the base IQsignal and supplies the generated signal to the antenna device 134 atthe subsequent stage. The above-described first through fourth controlvalues which define how the I signal and the Q signal will be combinedare generated by the phase controller 140, which will be discussedlater.

The signal mixer 132 shown in FIG. 1 mixes the I signal and the Q signaloutput from the phase shifter 131 and outputs the resulting IQ signal.

The RF transmitter 133 performs gain adjustment and up-conversion on theIQ signal (hereinafter called the transmission signal) output from thesignal mixer 132.

The antenna device 134 radiates the transmission signal up-converted bythe RF transmitter 133 around the wireless communication apparatus 100.

The phase controller 140 individually supplies the above-describedcontrol values to the phase shifters 131 so as to control thedirectivity of radio waves of transmission signals to be radiated fromthe first through N antenna devices 134 ₁ through 134 _(N). In thiscase, however, the phase controller 140 adjusts the control values to besupplied to the phase shifters 131 from default values which are set forperforming directivity control, thereby correcting transmission signalsfor quadrature errors (IQ errors).

The phase controller 140 includes a look-up table (LUT) 141, a phasesetting unit 142, a control value obtaining unit 143, a phase errorcorrecting unit 144, and an amplitude error correcting unit 145. Thephase error correcting unit 144 and the amplitude error correcting unit145 may be disposed outside the phase controller 140.

The look-up table 141 is a reference table in which the first throughfourth control values to be supplied to the phase shifters 131 aredescribed according to the phase θ to be supplied to each antenna device134. In this case, the values of the first through fourth controlsignals are those in a case in which transmission signals are notcorrected for quadrature errors. That is, the look-up table 141 is atable in which at least the values of cos θ and sin θ are described foreach θ.

The phase setting unit 142 sets the value of the phase (hereinafterreferred to as the “default phase”) θ for each antenna device 134 inaccordance with a predetermined pattern of directivity, and outputs thedefault phase θ which is set for each antenna device 134 to the controlvalue obtaining unit 143. That is, the phase setting unit 142 outputsfirst through N default phases θ₁ through θ_(N) in accordance with onepattern of directivity.

A certain pattern of directivity is selected from among a plurality ofprepared patterns of different directivity directions by, for example, ahigher application layer (not shown) included in the wirelesscommunication apparatus 100.

The control value obtaining unit 143 obtains, for each transmissionbranch 130, control values corresponding to the default phase θ set bythe phase setting unit 142 by referring to the look-up table 141, andsupplies the obtained control values to the corresponding phase shifter131. The control values to be supplied to one phase shifter 131 are, forexample, the first through fourth control values corresponding to cos θ,−sin θ, sin θ, and cos θ discussed with reference to FIGS. 2 and 3.

The phase error correcting unit 144 changes reference values (indexes)in the look-up table 141 at least for the third and fourth controlvalues which are referred to by the control value obtaining unit 143,thereby correcting transmission signals for phase errors. Details ofcorrections for phase errors performed by the phase error correctingunit 144 will be discussed later.

The amplitude error correcting unit 145 adjusts at least the first andsecond control values to be supplied from the control value obtainingunit 143 to the phase shifters 131, thereby correcting transmissionsignals for amplitude errors. Details of corrections for amplitudeerrors performed by the amplitude error correcting unit 145 will bediscussed later.

The wireless communication apparatus 100 includes a central processingunit (CPU), a storage medium, such as a read only memory (ROM), storinga control program therein, a work memory, such as a random access memory(RAM), and a communication circuit, although these elements are notshown. In this case, functions, such as the signal generator 110, thephase controller 140, and a higher application layer, are implemented asa result of the CPU executing the control program.

In the wireless communication apparatus 100 configured as describedabove, the phase shifter 131 that perform phase rotation for an IQsignal is disposed for each antenna device 134, and also, control valuesto be input into each phase shifter 131 can be adjusted. This enablesthe wireless communication apparatus 100, not only to performdirectivity communication using IQ signals, but also to correct IQsignals for quadrature errors by performing simple processing such as byadjusting control values to be input into the phase shifters 131.

(Corrections for Phase Errors and Amplitude Errors)

Details of phase error corrections and amplitude error corrections(quadrature error corrections) performed by the phase controller 140will be discussed below.

FIG. 6 is a conceptual diagram illustrating an example of the state inwhich quadrature errors are corrected. FIG. 7 illustrates an example ofthe detailed configuration of the phase controller 140 in associationwith operations performed by the individual elements of the phasecontroller 140.

In FIG. 6, I1 and Q1 represent the values of an I signal and a Q signalinput into a certain phase shifter 131 (hereinafter referred to as the“input values I1 and Q1”). I2 and Q2 represent the values of the Isignal and the Q signal which have not been corrected for quadratureerrors and output from the phase shifter 131 (hereinafter referred to asthe “intermediate values I2 and Q2”). I3 and Q3 represent the values ofthe I signal and the Q signal which have been corrected for quadratureerrors and output from the phase shifter 131 (hereinafter referred to asthe “output values I3 and Q3”).

Processing for obtaining the output values I3 and Q3 from the inputvalues I1 and Q1 can be considered as being separated into twooperations, for example, a phase rotation operation 221 for rotating thephase of the input values I1 and Q1 based on the default phase θ and aquadrature error correcting operation 222 for correcting theintermediate values I2 and Q2 for quadrature errors obtained by thephase rotation operation 221.

The phase rotation operation 221 is implemented by supplying valuescorresponding to cos θ, −sin θ, and cos θ as the first through fourthcontrol values to the phase shifter 131 configured as discussed withreference to FIGS. 2 and 3.

In the quadrature error correcting operation 222, the value obtained bymultiplying the I signal by a correction value α is output as a new Isignal, while the I signal is first multiplied by a correction value β,and then, the Q signal is added to this multiplication value and theresulting value is output as a new Q signal. In this case, the amplitudeerrors of the IQ signal are corrected for by the correction value α,while the phase errors of the IQ signal are corrected for by thecorrection value β.

The relationships between the input values I1 and Q1 and theintermediate values I2 and Q2 (phase rotation operation 221) may beexpressed by equations (1). Equations (1) represent the rotationoperation of the related art.

I2=cos θ·I1−sin θ·Q1

Q2=sin θ·I1+cos θ·Q1  (1)

The relationships between the intermediate values I2 and Q2 and theoutput values I3 and Q3 (quadrature error correcting operation 222) maybe expressed by equations (2).

I3=α·I2

Q3=β·I2+Q2  (2)

If the output values I3 and Q3 are expressed by using the input valuesI1 and Q1 by rearranging equations (1) and (2), equations (3) areestablished.

I3=α·cos θ·I1−α·sin θ·Q1

Q3=(β·cos θ+sin θ)·I1+(cos θ−β·sin θ)·Q1  (3)

The correction value β necessary for correcting phase errors isgenerally a value close to zero, and thus, it may be approximated asβ=sin β and cos β=1. Accordingly, equations (3) may be modified intoequations (4).

I3=α·cos θ·I1−α·sin θ·Q1

Q3=sin(θ+β)·I1+cos(θ+β)·Q1  (4)

Equations (4) are different from equations (1) merely in that,concerning the I signal, the I signal is uniformly multiplied by thecorrection value α and, concerning the Q signal, the default phase θ isreplaced by the value (θ+β) obtained by adding the correction value β toθ.

That is, it is possible to correct the IQ signal for amplitude errors inthe phase shifter 131 by multiplying each of the first control value(cos θ) and the second control value (−sin θ) obtained from the look-uptable 141 based on the default phase θ by the correction value α. It isalso possible to correct the IQ signal for phase errors in the phaseshifter 131 by changing the reference values (indexes) of the look-uptable 141 for obtaining the third control value (sin θ) and the fourthcontrol value (cos θ) from the default phase θ to θ′=θ+β.

Accordingly, as shown in FIG. 7, concerning the third and fourth controlvalues, the phase error correcting unit 144 adds the correction value βto the default phase θ used by the control value obtaining unit 143 asthe reference value (index value) in the look-up table 141. As a result,the phase controller 140 outputs sin(θ+β) and cos(θ+β) as the third andfourth control values, respectively.

As shown in FIG. 7, concerning the first and second control values, theamplitude error correcting unit 145 multiplies the values cos θ and −sinθ obtained by the control value obtaining unit 143 from the look-uptable 141 by the correction value α. As a result, the phase controller140 outputs α·cos θ and −α·sin θ as the first and second control values,respectively.

That is, if the phase controller 140 supplies the following controlvalues to a certain phase shifter 131 in a case in which there is noquadrature errors,

-   -   first control value=cos θ    -   second control value=−sin θ    -   third control value=sin θ    -   fourth control value=cos θ        the phase controller 140 supplies the following control values        to the same phase shifter 131 in the case of the occurrence of        amplitude errors that will be corrected for by the correction        value α and phase errors that will be corrected for by the        correction value β.    -   first control value=α·cos θ    -   second control value=−α·sin θ    -   third control value=sin(θ+β)    -   fourth control value=cos(θ+β)

The correction values α and β may be determined as follows. A table inwhich the value of amplitude errors and the correction value α areassociated with each other and a table in which the value of phaseerrors and the correction value β are associated with each other areprepared. Then, the correction values α and β are determined accordingto the values of the detected amplitude errors and phase errors byreferring to these tables. Alternatively, in order to optimize thecorrection values α and β, provisional values of the correction values αand β are sequentially determined while amplitude errors and phaseerrors are being detected. Then, the determined correction values α andβ are sequentially set in the amplitude error correcting unit 145 andthe phase error correcting unit 144, respectively.

With this configuration, the phase controller 140 realizes processingexpressed by equations (4) which reflect both of the phase rotationoperation 221 and the quadrature error correcting operation 222 by usingeach phase shifter 131.

Usually, processing for generating control values to be supplied to thephase shifters 131 is executed by digital signal processing. Thisenables the wireless communication apparatus 100, not only to easilyrealize the multiplication of the correction value α and changing of thereference values in the look-up table 141, but also to correct forquadrature errors with high precision, substantially without increasingthe circuit scale.

The phase controller 140 may use the look-up table 141 in which thevalue of cos θ is associated with the phase θ also as a look-up tablefor outputting the first and fourth control values.

The phase controller 140 may use the look-up table 141 in which thevalue of sine is associated with the phase θ also as a look-up table foroutputting the second and third control values. In this case, thecontrol value obtaining unit 143 inverts the sign of the value obtainedfrom the look-up table 141 and outputs the inverted value as the thirdcontrol value.

The phase controller 140 may use the look-up table 141 in which thevalue of cos θ or sin Θ is associated with the phase θ also as a look-uptable for outputting the first through fourth control values. In thiscase, the control value obtaining unit 143 obtains two control valuesfrom the look-up table 141 by shifting the phase θ by 2/π and invertsthe signs of the obtained two control values so as to obtain the firstthrough fourth control values.

(Operation of Wireless Communication Apparatus)

A flow of the operation of the wireless communication apparatus 100 willbe described briefly.

In the wireless communication apparatus 100, an IQ signal is generatedin the signal generator 110 and is converted into an analog IQ signal inthe D/A converter 120, and is then input into each of the first throughN transmission branches 130 ₁ through 130 _(N). Then, for each antennadevice 134, the wireless communication apparatus 100 combines the Isignal and the Q signal with each other in each of the first through Nphase shifters 131 ₁ through 131 _(N) by using the phase controller 140so as to generate transmission signals equivalent to signals obtained byrotating the phase of the base IQ signal. As a result, the wirelesscommunication apparatus 100 radiates transmission signals in which thedirectivity of radio waves is controlled from the first through Nantenna devices 134 ₁ through 134 _(N). Meanwhile, the phase controller140 corrects the transmission signals for quadrature errors by adjustingthe control values which define how the I signal and the Q signal willbe combined.

(Advantages of First Embodiment)

As described above, the wireless communication apparatus 100 accordingto the first embodiment includes the plurality of antenna devices 134,the signal generator 100, the phase shifter 131, the phase controller140, and the phase error correcting unit 144 and the amplitude errorcorrecting unit 145 (quadrature error correcting unit). The phasegenerator 100 generates an IQ signal constituted by an I signal and a Qsignal. The phase shifter 131 is provided for each of the plurality ofantenna devices 134. The phase shifter 131 generates a transmissionsignal equivalent to a signal obtained by rotating the phase of the IQsignal by combining the I signal and the Q signal with each other, andsupplies the transmission signal to the corresponding antenna device134. The phase controller 140 controls the directivity of radio waves ofthe transmission signals radiated from the plurality of antenna devices134 by individually supplying control values which define how the Isignal and the Q signal will be combined to the phase shifters 131. Thephase error correcting unit 144 and the amplitude error correcting unit145 correct the transmission signals for quadrature errors by adjustingthe above-described control values.

That is, in the wireless communication apparatus 100 according to thefirst embodiment, values determined by considering quadrature errors areused as control values to be set in the phase shifter 131 provided ineach transmission branch 130 in a phased array system.

With this configuration, in addition to phase control for beamforming,the wireless communication apparatus 100 according to the firstembodiment is able to make corrections for IQ errors for eachtransmission branch 130 by using a simple technique such as adjusting ofcontrol values.

That is, the wireless communication apparatus 100 according to the firstembodiment is able to perform directivity communication by using IQsignals corrected for quadrature errors, substantially withoutincreasing the circuit scale.

If the above-described related art is applied to a phased array system,an analog circuit for correcting for quadrature errors is provided foreach antenna device, as discussed above. The circuit scale of an analogcircuit is usually larger than that of a digital circuit, and thecorrection characteristics of the analog circuit are more likely todeteriorate due to the influence of process variations and temperaturechange. Thus, the wireless communication apparatus 100 according to thefirst embodiment is able to perform higher-precision quadrature errorcorrections than the related art.

An analog IQ correcting circuit that performs the quadrature errorcorrecting operation 222 shown in FIG. 6 may be provided at thesubsequent stage of each phase shifter 131. However, the configurationin which an analog IQ correcting circuit is disposed in eachtransmission branch 130 increases the circuit scale and also makes itdifficult to perform high-precision quadrature error corrections. Thus,compared with this configuration, the wireless communication apparatus100 according to the first embodiment is able to performhigher-precision quadrature error corrections with the reduced circuitscale.

The D/A converter 120 may be disposed in each transmission branch 130and an IQ correcting circuit that performs the quadrature errorcorrecting operation 222 shown in FIG. 6 may be provided at the previousstage of each D/A converter 120. In this case, it is possible to performhigher-precision quadrature error corrections than the use of an analogIQ correcting circuit. On the other hand, however, the configuration inwhich the D/A converter 120 and the digital IQ correcting circuit aredisposed in each transmission branch 130 significantly increases thecircuit scale. Thus, compared with this configuration, in the wirelesscommunication apparatus 100 according to the first embodiment, thecircuit scale can be significantly reduced.

Second Embodiment

In a second embodiment of the present disclosure, the function of theamplitude error correcting unit 145 of the first embodiment isimplemented by an amplitude error correcting circuit provided in eachtransmission branch.

(Configuration of Wireless Communication Apparatus)

The configuration of a wireless communication apparatus of the secondembodiment will first be discussed below.

FIG. 8 is a block diagram illustrating an example of the configurationof a wireless communication apparatus 100 a according to the secondembodiment. FIG. 8 corresponds to FIG. 1 illustrating the firstembodiment. In FIG. 8, the same elements as those shown in FIG. 1 aredesignated by like reference numerals, and an explanation thereof willthus be omitted.

As shown in FIG. 8, the wireless communication apparatus 100 a includesa signal generator 110, a D/A converter 120, first through Ntransmission branches 130 a ₁ through 130 a _(N), and a phase controller140 a.

Each of the transmission branches 130 a includes a phase shifter 131, asignal mixer 132, an RF transmitter 133, and an antenna device 134. Inthe second embodiment, the transmission branch 130 a also includes anamplitude error correcting circuit 135 a interposed between the phaseshifter 131 and the signal mixer 132. The phase controller 140 a doesnot have the amplitude error correcting unit 145 provided in the phasecontroller 140 of the first embodiment.

That is, in the second embodiment, the amplitude error correctingfunction implemented by the amplitude error correcting unit 145 of thephase controller 140 of the first embodiment is implemented by theamplitude error correcting unit 135 a disposed in each transmissionbranch 130 a. The phase controller 140 a without an amplitude errorcorrecting function corrects only for phase errors by using each phaseshifter 131.

The amplitude error correcting circuit 135 a provides different degreesof amplification to the I signal and the Q signal. That is, theamplitude error correcting circuit 135 a at least includes a gainamplifier for adjusting the amplitude of at least one of the I signaland the Q signal. For example, the amplitude error correcting circuit135 a includes a circuit for amplifying the I signal by varying the gainand a circuit for amplifying the Q signal by varying the gain.

(Corrections for Phase Errors and Amplitude Errors)

Details of phase error corrections and amplitude error correctionsperformed by the phase controller 140 a will be discussed below.

FIG. 9 is a conceptual diagram illustrating an example of the state inwhich quadrature errors are corrected in the second embodiment. FIG. 9corresponds to FIG. 6 illustrating the first embodiment. FIG. 10illustrates an example of the detailed configuration of the phasecontroller 140 a in association with operations performed by theindividual elements of the phase controller 140 a. FIG. 10 correspondsto FIG. 7 illustrating the first embodiment. The same elements as thoseshown in FIGS. 6 and 7 are designated by like reference numerals andsigns, and an explanation thereof will thus be omitted.

In FIG. 9, I3′ and Q3′ (intermediate values) represent the values of theI signal and the Q signal which have been corrected for phase errors andoutput from the phase shifter 131. I4 and Q4 (output values) representthe values of the I signal and the Q signal which have been correctedfor amplitude errors and output from the amplitude error correctingcircuit 135 a.

The relationships between the input values I1 and Q1 and theintermediate values I2 and Q2 (phase rotation operation 221) areexpressed by equations (1), as in the first embodiment.

Processing for obtaining the output values I4 and Q4 from theintermediate values I2 and Q2 can be considered as being separated intotwo operations, for example, a phase error correcting operation 222 ₁performed on the intermediate values I2 and Q2 and an amplitude errorcorrecting operation 222 ₂ performed on the intermediate values I3′ andQ3′ obtained by performing the phase error correcting operation 222 ₁.

The relationships between the intermediate values I2 and Q2 and theintermediate values I3′ and Q3′ (phase error correcting operation 222 ₁)may be expressed by equations (5).

I3′=I2

Q3′=βI2+Q2  (5)

If the intermediate values I3′ and Q3′ are expressed by using the inputvalues I1 and Q1 by rearranging equations (1) and (5), equations (6) areestablished.

I3′=cos θ·I1−sin θ·Q1

Q3′=(β·cos θ+sin θ)·I1+(cos θ−β·sin θ)·Q1  (6)

As in the first embodiment, if the correction value β is approximated asβ=sin β and cos β=1, equations (6) may be modified into equations (7).

I3′=cos θ·I1−sin θ·Q1

Q3′=sin(θ+β)·I1+cos(θ+β)·Q1  (7)

As a result of comparing equations (7) with equations (1), it is seenthat, concerning the I signal, there is no difference, and concerningthe Q signal, the difference between equations (1) and (7) is merelythat the default phase e is replaced by the value (θ+β) obtained byadding the correction value β to θ.

That is, if the phase controller 140 a supplies the following controlvalues to a certain phase shifter 131 in a case in which there is noquadrature errors,

-   -   first control value=cos θ    -   second control value=−sin θ    -   third control value=sin θ    -   fourth control value=cos θ        the phase controller 140 a supplies the following control values        to the same phase shifter 131 in the case of the occurrence of        amplitude errors that will be corrected for by the correction        value α and phase errors that will be corrected for by the        correction value β.    -   first control value=cos θ    -   second control value=sin θ    -   third control value=sin(θ+β)    -   fourth control value=cos(θ+β)        Corrections for amplitude errors that will be corrected for by        the correction value α are performed by the amplitude error        correcting circuit 135 a.

The relationships between the intermediate values I3′ and Q′ and theoutput values I4 and Q4 (amplitude error correcting operation 222 ₂) maybe expressed by equations (8).

I4=α·I3′

Q4=Q3′  (8)

If the output values I4 and Q4 are expressed by using the input valuesI1 and Q1 by rearranging equations (7) and (8), equations (9) areestablished.

I4=α·cos θ·I1−α·sin θ·Q1

Q4=sin(θ+β)·I1+cos(θ+β)·Q1  (9)

The output values I4 and Q4 from the amplitude error correcting circuit135 a are handled similarly to the output values I3 and Q3 from thephase shifter 131 in the first embodiment and are input into the signalmixer 132. Accordingly, equations (9) are equivalent to equations (4) inthe first embodiment.

Thus, although the phase controller 140 a does not include the amplitudeerror correcting unit 145 as shown in FIG. 10, the amplitude errorcorrecting circuit 135 a provided in each transmission branch 130 amultiplies the I signal by the correction value α (or divides the Qsignal by the correction value α) so as to perform quadrature errorcorrections similar to those in the first embodiment. That is, theamplitude error correcting circuit 135 a adjusts the amplitude of atleast one of the I signal and the Q signal, thereby making it possibleto perform amplitude error corrections for a transmission signal to beradiated from the corresponding antenna device 134.

(Operation of Wireless Communication Apparatus)

A flow of the operation of the wireless communication apparatus 100 awill be described briefly. The operation of the wireless communicationapparatus 100 a is similar to that of the wireless communicationapparatus 100 of the first embodiment. However, among quadrature errorsto be corrected for, only phase errors are corrected for in the phasecontroller 140 a by adjusting control values to be supplied to the phaseshifters 131, and amplitude errors are corrected for, separately fromphase errors, from signals output from the phase shifters 131(transmission signals in which the directivity of radio waves iscontrolled).

(Advantages of Second Embodiment)

As described above, the wireless communication apparatus 100 a accordingto the second embodiment corrects an IQ signal for amplitude errors byusing the amplitude error correcting circuit 135 a provided in eachtransmission branch 130 a, instead of by adjusting control values to besupplied to the phase shifter 131.

It is possible to form the circuit scale of the amplitude errorcorrecting circuit 135 a smaller than that of the IQ correcting circuitof the related art. Thus, compared with the related art, the wirelesscommunication apparatus 100 a according to the second embodiment is ableto perform directivity communication by using IQ signals corrected forquadrature errors with a reduced circuit scale.

In the second embodiment, the multiplication of the correction value αfor correcting for amplitude errors is performed, not on control valuesto be supplied to the phase shifter 131, but on an IQ signal output fromthe phase shifter 131. With this configuration, the wirelesscommunication apparatus 100 a is advantageous over the wirelesscommunication apparatus 100 of the first embodiment in that it is ableto correct for amplitude errors while avoiding the influence of, forexample, any change made to the phase shifter 131 or a decrease in thephase control precision.

This will be explained more specifically. If the phase θ=0° is appliedto an IQ signal for a certain transmission branch 130 a, the value ofcos θ corresponding to the first and fourth control values is 1.0.

If, for example, a combination of a sign one bit and the absolute valueof five bits is a control value to be supplied to the phase shifter 131,1·1/2+1·1/4+1·1/8+1·1/16+1·1/32=31/3231/32 is considered as 1.0. Thatis, the control value obtaining unit 143 multiplies a control value tobe supplied to the phase shifter 131 by 31/32, and the value obtained byperforming bit conversion of a power of two on the resultingmultiplication value is set to be the absolute value of five bits. Thatis, the first and fourth control values to be input into the phaseshifter 131 when θ=0° is “0_11111”.

In this case, if amplitude corrections are performed by using thecorrection value α=1.2, the first and fourth control values to be inputinto the phase shifter 131 are α·cos θ=1.2, that is, 1.2×31/32≈37/32.However, if the phase shifter 131 has only five-stage amplifiers 211corresponding to 1/2, 1/4, 1/8, 1/16, and 1/32 (see FIG. 4), it isunable to generate a current of 37/32 and is thus unable to set α>1.

In this case, certain measures may be taken, for example, six-stageamplifiers 211 including an amplifier 211 corresponding to 1 may beprepared, in which case, however, an extra amplifier 211 has to be addedto the phase shifter 131. Alternatively, the overall scale may beuniformly reduced to half while the five-stage amplifiers 211 aremaintained, in which case, however, the bit precision for phase controlis decreased.

In the wireless communication apparatus 100 a according to the secondembodiment, the multiplication of the correction value α is notperformed on the control value to be supplied to the phase shifter 131.Thus, amplitude error corrections can be performed while avoiding theinfluence of the addition of an amplifier 211 to the phase shifter 131or a decrease in the phase control precision.

If a wireless communication apparatus includes a circuit for uniformlyamplifying the IQ signal by varying the gain, this circuit may simply bemodified so that it can perform amplification control separately for theI signal and the Q signal. Then, a function equivalent to the functionof the amplitude error correcting circuit 135 a can be added.

Third Embodiment

In a third embodiment, quadrature error corrections discussed in thefirst embodiment are performed in a receiving system of a wirelesscommunication apparatus that receives a radio signal by using an arrayantenna including N antenna devices.

FIG. 11 is a block diagram illustrating an example of the configurationof a wireless communication apparatus 100 b according to the thirdembodiment. FIG. 11 corresponds to FIG. 1 illustrating the firstembodiment. In FIG. 11, the same elements as those shown in FIG. 1 aredesignated by like reference numerals, and an explanation thereof willthus be omitted.

As shown in FIG. 11, the wireless communication apparatus 100 b includesfirst through N reception branches 150 b ₁ through 150 b _(N), a phasecontroller 140, an analog-to-digital (A/D) (ADC) converter 160 b, and asignal processor 170 b.

Each reception branch 150 b includes an antenna device 151 b, an RFreceiver 152 b, a signal separator 153 b, and a phase shifter 154 b.

The antenna device 151 b receives a radio signal.

The RF receiver 152 b performs gain adjustment and down-conversion onthe radio signal received by the antenna device 151 b.

The signal separator 153 b extracts an analog IQ signal from the radiosignal down-converted by the RF receiver 152 b and outputs the analog IQsignal in a state in which the I signal and Q signal are separated fromeach other.

On the basis of control values supplied from the phase controller 140,the phase shifters 154 b of the respective transmission branches 150 bprovide different phases to the IQ signal output from the signalseparator 153 b. The configuration and operation of the phase shifter154 b are similar to those of the phase shifter 131 of the firstembodiment. However, the phase shifter 154 b performs phase rotation forthe IQ signal in order to control the reception directivity in the arrayantenna.

The A/D converter 160 b combines the IQ signals output from the firstthrough N phase shifters 154 b ₁ through 154 b _(N) and performs A/Dconversion on the combined IQ signal so as to generate a digital IQsignal.

The signal processor 170 b extracts information from the digital IQsignal output from the A/D converter 160 b, and supplies the extractedinformation to, for example, a higher application layer.

In the wireless communication apparatus 100 b configured as describedabove, in a reception system that receives an IQ signal by controllingthe directivity, quadrature error corrections can be performed on the IQsignal substantially without increasing the circuit scale.

Fourth Embodiment

In a fourth embodiment of the present disclosure, the function of theamplitude error correcting unit 145 of the third embodiment isimplemented by an amplitude error correcting circuit provided in eachreception branch, such as that discussed in the second embodiment.

FIG. 12 is a block diagram illustrating an example of the configurationof a wireless communication apparatus 100 c according to the fourthembodiment. FIG. 12 corresponds to FIG. 8 illustrating the secondembodiment and FIG. 11 illustrating the third embodiment. In FIG. 12,the same elements as those shown in FIGS. 8 and 11 are designated bylike reference numerals, and an explanation thereof will thus beomitted.

As shown in FIG. 12, the wireless communication apparatus 100 c includesfirst through N reception branches 150 c ₁ through 150 c _(N), a phasecontroller 140 a, an A/D converter 160 b, and a signal processor 170 b.

Each of the reception branches 150 c includes an antenna device 151 b,an RF receiver 152 b, a signal separator 153 b, and a phase shifter 154b. In the fourth embodiment, the reception branch 150 c also includes anamplitude error correcting circuit 155 c interposed between the signalseparator 153 b and the phase shifter 154 b.

The amplitude error correcting circuit 155 c provides different degreesof amplification to the I signal and the Q signal. The configuration andoperation of the amplitude error correcting circuit 155 c are similar tothose of the amplitude error correcting circuit 135 a of the secondembodiment.

In the wireless communication apparatus 100 c configured as describedabove, in a reception system that receives IQ signals by controlling thedirectivity, quadrature error corrections can be performed on IQsignals. In particular, quadrature error corrections can be performedsubstantially without increasing the circuit scale and by avoiding theinfluence of, for example, any change made to the phase shifter 154 b ora decrease in the phase control precision.

Modified Examples of the Embodiments

The configurations of the wireless communication apparatuses of theabove-described first through fourth embodiments may be modified.

For example, the phase controller may store in advance a look-up tableprepared for each correction value β in which control values thatreflect the correction value β are described, and may change the look-uptable for reference according to the correction value β.

In the above-described embodiments, the I signal and the Q signal may beread as (replaced by) the Q signal and the I signal, respectively, andmay be applied to the wireless communication apparatus.

The wireless communication apparatus may not necessarily include anamplitude error correcting unit or an amplitude error correctingcircuit. That is, the wireless communication apparatus may perform onlyphase error corrections among quadrature error corrections.

Conversely, the wireless communication apparatus may not necessarilyinclude a phase error correcting unit. That is, the wirelesscommunication apparatus may perform only amplitude error correctionsamong quadrature error corrections.

CONCLUSIONS OF THE PRESENT DISCLOSURE

A wireless communication apparatus according to an aspect of the presentdisclosure includes a plurality of antenna devices, signal generatingcircuitry, a plurality of phase shifting circuitry, phase controllingcircuitry, and quadrature error correcting circuitry. The signalgenerating circuitry, in operation, generates an IQ signal having an Isignal and a Q signal. The plurality of phase shifting circuitryprovided for each of the plurality of antenna devices, in operation,generates a plurality of combination signals by combining the I signaland the Q signal based on a predetermined combining scheme. The phasecontrolling circuitry, in operation, controls the predeterminedcombining scheme in each of the plurality of phase shifting circuitry.The quadrature error correcting circuitry, in operation, corrects atleast one of amplitude combining scheme and phase combining scheme ofthe predetermined combining scheme in a correction of the predeterminedcombining scheme.

In the wireless communication apparatus, the combining scheme mayinclude rotate calculations for the IQ signal in a complex plane.

In the wireless communication apparatus, the plurality of phase shiftingcircuitry may generate a new I signal of the combination signal byadding the I signal multiplied a first control value and the Q signalmultiplied a second control value, and may generate a new Q signal ofthe combination signal by adding the I signal multiplied a third controlvalue and the Q signal multiplied a fourth control value. The phasecontrolling circuitry individually may supply the first through fourthcontrol values to the phase shifter.

In the wireless communication apparatus, the phase controlling circuitrymay include a reference table that contains the first through fourthcontrol values to be supplied to the phase shifting circuitry, the firstthrough fourth values being provided at each pattern of directivity ofthe plurality of antenna devices. Phase setting circuitry, in operation,may set a value of the phase for each of the plurality of antennadevices in accordance with a predetermined pattern of directivity.Control value obtaining circuitry, in operation, may obtain the firstthrough fourth control values corresponding to the set value of thephase by referring to the reference table and supplies the obtainedfirst through fourth control values to the plurality of phase shiftingcircuitry. The quadrature error correcting circuitry may include phaseerror correcting circuitry which, in operation, may modify the obtainedthird and fourth control values, the modified third and fourth controlvalues being supplied to each of the plurality of phase shiftingcircuitry.

In the wireless communication apparatus, the quadrature error correctingcircuitry may further include amplitude error correcting circuitrywhich, in operation, modifies the obtained first and second controlvalues, the modified first and second control values being supplied toeach of the phase shifting circuitry.

In the wireless communication apparatus, the quadrature error correctingcircuitry may further include amplitude error correcting circuitry,provided for each of the plurality of antenna devices which, inoperation corrects the amplitude of at least one of the I signal and theQ signal of the combination signal.

A wireless communication method according to an aspect of the presentdisclosure is a wireless communication method using a plurality ofantenna devices. The wireless communication method includes: generatingan IQ signal having an I signal and a Q signal; generating a pluralityof combination signals by combining the I signal and the Q signal basedon a predetermined combining scheme by using a plurality of phaseshifting circuitry; controlling the predetermined combining scheme ineach of the plurality of phase shifting circuitry; and correcting atleast one of amplitude combining scheme and phase combining scheme ofthe predetermined combining scheme in a correction of the predeterminedcombining scheme.

Various embodiments have been described above with reference to thedrawings, but the present disclosure is not limited to these examples.It is clear that a person skilled in the art can arrive at variouschanges or modifications within the scope described in the claims, andit is understood that these changes or modifications are alsoencompassed within the technical scope of the present disclosure.Furthermore, the constituent elements in the embodiments may be combinedin any ways as long as the combination is not deviated from the purposeof the present disclosure.

In the embodiment above, a case where the present disclosure is realizedby using hardware has been described as an example. However, the presentdisclosure may be realized by software in combination with hardware.

The functional blocks used for description of the embodiment aretypically realized as an LSI which is an integrated circuit having aninput terminal and an output terminal. These functional blocks may berealized as individual chips or some or all of the functional blocks maybe realized as a single chip. The term “LSI” is used, but the term “IC”,“system LSI”, “super LSI”, or “ultra LSI” may be used depending on thedegree of integration.

Furthermore, means to achieve integration is not limited to an LSI andmay be a special circuit or a general-purpose processor. An FPGA (FieldProgrammable Gate Array) that can be programmed after production of anLSI or a reconfigurable processor in which connection or setting ofcircuit cells inside an LSI can be reconfigured can be also used.

If a technique of integration circuit that replaces an LSI appears inthe future as a result of advancement of the semiconductor technique orappearance of another technique deriving from the semiconductortechnique, integration of the functional blocks can be achieved by usingsuch a technique. One possibility is application of biotechnology.

The wireless communication apparatus and method according to an aspectof the present disclosure is suitably used as a wireless communicationapparatus and method that is able to perform directivity communicationby using IQ signals corrected for quadrature errors, substantiallywithout increasing the circuit scale.

What is claimed is:
 1. A wireless communication apparatus comprising: aplurality of antenna devices; signal generating circuitry which, inoperation, generates an IQ signal having an I signal and a Q signal; aplurality of phase shifting circuitry, provided for each of theplurality of antenna devices, which, in operation, generates a pluralityof combination signals by combining the I signal and the Q signal basedon a predetermined combining scheme; phase controlling circuitry which,in operation, controls the predetermined combining scheme in each of theplurality of phase shifting circuitry; and quadrature error correctingcircuitry which, in operation, corrects at least one of amplitudecombining scheme and phase combining scheme of the predeterminedcombining scheme in a correction of the predetermined combining scheme.2. The wireless communication apparatus according to claim 1, whereinthe combining scheme includes rotate calculations for the IQ signal in acomplex plane.
 3. The wireless communication apparatus according toclaim 2, wherein: the plurality of phase shifting circuitry generates anew I signal of the combination signal by adding the I signal multiplieda first control value and the Q signal multiplied a second controlvalue, and generates a new Q signal of the combination signal by addingthe I signal multiplied a third control value and the Q signalmultiplied a fourth control value; the phase controlling circuitryindividually supplies the first through fourth control values to thephase shifting circuitry.
 4. The wireless communication apparatusaccording to claim 3, wherein the phase controlling circuitry includes areference table that contains the first through fourth control values tobe supplied to the phase shifting circuitry, the first through fourthvalues being provided at each pattern of directivity of the plurality ofantenna devices, phase setting circuitry which, in operation, sets avalue of the phase for each of the plurality of antenna devices inaccordance with a predetermined pattern of directivity, control valueobtaining circuitry which, in operation, obtains the first throughfourth control values corresponding to the set value of the phase byreferring to the reference table and supplies the obtained first throughfourth control values to the plurality of phase shifting circuitry, andthe quadrature error correcting circuitry includes phase errorcorrecting circuitry which, in operation, modifies the obtained thirdand fourth control values, the modified third and fourth control valuesbeing supplied to each of the plurality of phase shifting circuitry. 5.The wireless communication apparatus according to claim 4, wherein thequadrature error correcting circuitry further includes amplitude errorcorrecting circuitry which, in operation, modifies the obtained firstand second control values, the modified first and second control valuesbeing supplied to each of the phase shifting circuitry.
 6. The wirelesscommunication apparatus according to claim 4, wherein the quadratureerror correcting circuitry further includes amplitude error correctingcircuitry, provided for each of the plurality of antenna devices which,in operation corrects the amplitude of at least one of the I signal andthe Q signal of the combination signal.
 7. A wireless communicationmethod using a plurality of antenna devices, comprising: generating anIQ signal having an I signal and a Q signal; generating a plurality ofcombination signals by combining the I signal and the Q signal based ona predetermined combining scheme by using a plurality of phase shiftingcircuitry; controlling the predetermined combining scheme in each of theplurality of phase shifting circuitry; and correcting at least one ofamplitude combining scheme and phase combining scheme of thepredetermined combining scheme in a correction of the predeterminedcombining scheme.